Methods, devices and systems for counterpulsation of blood flow to and from the circulatory system

ABSTRACT

Counterpulsation methods and systems for assisting the heart of a patient involve, for example, coordinating the operation of a pulsatile pump to suction blood from an artery through a first conduit while the heart is in systole and expel the blood into the first conduit and the artery while the heart is in diastole.

This application is a continuation of application Ser. No. 11/841,244,filed Aug. 20, 2007 (pending) which is a continuation of applicationSer. No. 10/978,876, filed Nov. 1, 2004 (now U.S. Pat. No. 7,273,446)which claims the benefit of U.S. Provisional Application No. 60/516,529filed on Oct. 31, 2003 (expired), the disclosures of which are herebyincorporated by reference herein.

BACKGROUND OF THE INVENTION

Congestive heart failure is a major problem in today—over 5 millionpatients in the U.S. and probably even more in the EU are afflicted.There is no effective medication to improve the strength of heartcontraction and to date there has been little advancement toward solvingthis problem on a mass scale. Attempts should be directed to a simple,proven and minimally invasive system to help these patients.

Aortic counterpulsation is a well-established form of assistance for afailing heart. In one type of counterpulsation procedure, as the heartejects blood in systole, blood is removed from the aorta thus relievingthe work of the heart in ejecting blood. As the heart relaxes indiastole, the removed blood is pumped back into the aorta increasing theblood pressure and flow to the organs. This assists the heart for tworeasons. First, the work on the heart is reduced because blood iswithdrawn from the aorta as the heart is working (cardiac unloading).Second, the heart is unusual among organs in that most of its perfusionoccurs during diastole so that higher pressures during diastole cause amajor improvement to the flow of blood in the heart. Improved perfusionand oxygenation of the heart and reduced work performed by the hearttypically result in improved performance of the heart and improvedcirculation for the entire body. Many patients have been saved fromcertain death by application of this concept. Failing hearts and vitalorgans such as kidneys are frequently resuscitated by this method.

Most commonly, counterpulsation is achieved with a balloon inside theaorta rather than actually removing blood and returning blood to theaorta. This device is known as the intraaortic balloon pump. In practicea patient receives a balloon mounted (usually about 40 ml in size) on acatheter (1-2 m long). The catheter is introduced into the patient via agroin artery. The balloon resides in the descending aorta (beyond thetake-off of the vessels to the head and neck). The balloon is deflatedin systole to help the heart eject (rather than remove the blood) andinflated in diastole (rather than return the blood). The balloon isinflated and deflated by gas (usually helium) which is shuttled in andout of the catheter. The passage of the gas is driven and controlled bya console which times or coordinates the movement of gas with thepatient's EKG to ensure that the optimal timing of the inflation anddeflation occurs to ensure maximal improvement in cardiac performanceresults.

The intraaortic balloon pump has a number of major drawbacks. First, itis almost always inserted by a puncture in a major groin artery. Thepatient must remain supine in bed. Movement is extremely limited asmovement on the catheter may cause bleeding from the artery which hasbeen punctured. Patients often deteriorate while supine as musclesweaken from inactivity and the risk of pneumonia and leg clotsincreases.

Infection is also a major concern. The catheter travels out of the groinartery of the patient. Any catheter tracking into the body tends tobecome colonized with bacteria. Over time the bacteria travel up thecatheter and into the blood stream. As the groin area is plentiful withbacteria, this area is particularly ripe for the origin of infection.

Another concern is that of limb ischemia. The catheter may be close tothe size of the patients groin artery and may occlude the flow of bloodto the leg and risking the loss of that limb. Even when the groinarteries are large, over time clotting tends to occur around thecatheter and flow becomes reduced to the limb beyond the entry site.After a number of days there is an increasing risk of leg ischemia andleg loss.

In clinical practice, an intraaortic balloon pump usually remains inplace just a day or two. If it is left more than about a week, thedoctors become extremely concerned that a serious complication willoccur and typically remove the balloon.

Many patients have chronically weakened hearts that require long-termsupport. Despite the fact that counterpulsation is extremely helpful tothese patients, there has been no way to apply this technologypractically for a long period of time (i.e., months or years). It wouldbe very valuable for patients to have a system that providescounterpulsation but does not carry the risks of the intraaortic balloonpump.

Furthermore, these patients are very ill and cannot tolerate majorprocedures. An attempt has been described to perform long-termcounterpulsation by opening the patient's chest and then sewing aballoon pouch inside the aorta. This pouch is then attached to a driveline. Initial studies suggest that this does indeed provide considerablelong term help to a failing heart. However, it is unlikely that thisprocedure could ever be used on a large scale as it is so invasive. Inanother approach, the counterpulsation pouch has been sewn to thethoracic or abdominal aorta. However, this requires a major procedure—athoracotomy or a laparotomy to gain entry to the chest or abdominalcavity.

Blood pumps have also been used to assist the failing heart. In general,blood is taken from the left atrium or left ventricle and then pumpedinto the aorta. This form of cardiac assist is extremely effective.However, there are a number of problems that have not beensatisfactorily solved and this technology is not yet widely used inheart failure. The first problem is that insertion of these devicesrequires a major procedure for connection to the heart and the aorta.The pumps have blood contacting surfaces, particularly bearings, andthese are prone to clotting. Clots may either break loose and embolize(migrate) to the body causing strokes or other organ problems or maystay in place and enlarge to the point that they cause the device tomalfunction. The systems also contain valves which regulate thedirection of flow in the system. These valves, in combination withstasis points within the system may also contribute to clotting. Anothermajor problem with these devices is that they require major regulation.It is never clear how much blood should be pumped. If too little ispumped, the patient suffers from insufficient circulation. If the pumpis set too high, the heart can be sucked flat and then drawn into thepump with serious consequences to the heart. Patients in heart failurehave considerable variation over time in the fluid volume of theirhearts and the flow rates in the circulation. If the pump does notprecisely respond to these variations, failure may occur.

Counterpulsation eliminates many of the problems with blood pumping.There is no necessity for pump bearing-to-blood contact as the blood canfill and empty from a blood sac insulated from the driving pump ordevice. No valves are necessary. Stasis is minimal as the blood fillsand empties completely from the blood sac on each cardiac cycle. Perhapsmost important is that the regulation of this device is simple. Thesystem is not connected directly to the heart. Thus it can fill andempty each cycle without the need to adjust the volume that is pumped bythe system.

In summary, aortic counterpulsation is a proven form of heart assist inacute and chronic heart failure. Unfortunately, no chronic form has beendeveloped that can be provided to the patient in a minor procedure,allows mobility and reduces the risk of long term infection. Such asystem would be very useful to the millions of patients suffering fromcongestive heart failure.

SUMMARY OF THE INVENTION

In one embodiment, the present invention provides a counterpulsationmethod of assisting the heart of a patient using a pump assist systemwith the method comprising coupling a first conduit to the arterialsystem of the patient without entering the chest cavity or abdominalcavity of the patient. A pulsatile pump is connected to the firstconduit and the pump is implanted in the patient without entering thechest cavity or abdominal cavity of the patient. The power supply isconnected to the pump and the operation of the pump is coordinated tosuction blood from the arterial system through the first conduit whilethe heart is in systole and expel the blood into the first conduit andthe arterial system while the heart is in diastole. The power supply maybe mounted within the patient's body, outside the patient's body, orwith respective portions of the power supply system located inside andoutside the body.

The method can further include coupling a second conduit to the firstconduit, and coupling the second conduit to the arterial system withoutentering the chest cavity or the abdominal cavity of the patient. Againthe pulsatile pump operation is coordinated to suction blood from thearterial system through the first and second conduits while the heart isin systole and expel the blood into the arterial system while the heartis in diastole. Coupling the first and second conduits to the arterialsystem can further comprise coupling the first and second conduits todifferent arteries in the system. Another option is to couple the firstand second conduits to the same artery. It will be appreciated that theconduit(s) may be preconnected to the pump.

In accordance with another aspect or embodiment of the invention, themethod can further include connecting a second, continuous pump to thepatient for purposes of assisting blood flow from the heart. This may beaccomplished by directing another conduit into the left side of theheart, and yet another conduit to the arterial system of the patient. Acontinuous pump is connected between these conduits, and preferablyimplanted in the patient. A power supply, which may be the same as,coupled with, or different from the power supply for the pulsatile pump,is connected to the continuous pump. The method then further includessuctioning blood from the left side of the heart by way of thecontinuous pump and expelling the blood into the arterial system of thepatient.

The conduit or conduits of the invention may be coupled to asuperficial, subcutaneous artery of the patient, such as one or morearteries in the neck, shoulder or upper chest region of the patient.Alternatively, the artery may be located in the retroperitoneal regionof the patient, such as the distal aorta, iliac, external iliac,internal iliac or femoral artery systems. The pump may be, for example,implanted in the pelvic region and, more specifically, even in theretroperitoneal region. Although this latter location would be somewhatmore invasive than, for example, a superficial region of the chest, itis still much less invasive than intraabdominal or intrathoracicprocedures. A direct connection to the aorta may be accomplished withone or more conduits, and with the pump located in the superficial upperchest region similar to a pacemaker. Again, although the connection tothe aorta is invasive, the superficial location of the pump makes theoverall procedure much less invasive than conventional invasiveprocedures and less traumatic to the patient.

In another embodiment, the method includes coupling a first conduit tothe arterial system without entering the chest cavity or abdominalcavity of the patient, coupling a second conduit to the arterial systemof the patient without entering the chest cavity or abdominal cavity ofthe patient, and connecting a pump between the first and secondconduits. The pump suctions blood from the arterial system through thefirst conduit and expels the blood into the arterial system. As oneoption, the pump may expel blood through both the first and secondconduits while in another option, the blood may be expelled from thepump through only the second conduit through the use, for example, ofappropriate valving.

In another embodiment of the method, the pump is implanted in thepatient without entering the chest cavity or abdominal cavity of thepatient and the first conduit is coupled to the arterial system and tothe pump. The coupling of the first conduit to the arterial system may,in this embodiment, be through a superficial, subcutaneous connection ora more invasive procedure. In another embodiment, the first conduit maybe coupled to the arterial system without entering the chest cavity orabdominal cavity of the patient, and the pump may be located within thepatient, such as superficially, or more invasively, or the pump may belocated outside the patient.

A system for supplementing blood flow from the heart of a patient andproviding counterpulsation blood flow comprises a first conduitconfigured to directed into the left side of the heart, a second conduitconfigured to be coupled to the arterial system of the patient, and acontinuous pump configured to be connected with the first and secondconduits. A third conduit is configured to be coupled to the arterialsystem of the patient. A pulsatile pump is configured to be connectedwith the third conduit. At least one power supply is coupled to thepumps. At least one control operates the continuous pump to suctionblood from the left side of the heart through the first conduit andexpel blood from the continuous pump into the second conduit and thearterial system, and operates the pulsatile pump to suction blood fromthe arterial system through the third conduit while the heart is insystole and expel the blood from the pulsatile pump into the arterialsystem while the heart is in diastole.

A pulsatile counterpulsation pump for use in assisting the heart of apatient, in accordance with the invention, comprises a pump housinghaving a chamber and an inlet and an outlet in fluid communication withthe chamber. A movable member is mounted in the housing and suctionsblood into the inlet and expels blood from the outlet in a pulsatilemanner. A flushing fluid inlet communicates with the chamber forintroducing a flushing fluid into the chamber and reducing bloodclotting.

In another embodiment, a pulsatile counterpulsation pump includes a pumphousing having a chamber and an inlet and an outlet in fluidcommunication with the chamber. A movable member is mounted in thehousing and suctions blood into the inlet in a first stroke and expelsblood from the outlet in a second stroke. The chamber may be evacuatedof at least substantially all blood at the end of the second stroke, forexample, by use of the movable member itself, through the use of aseparate element from the movable member, or a combination of both.

Various additional features and advantages of the invention will becomemore readily apparent to those of ordinary skill in the art upon reviewof the following detailed description of various illustrative examples,taken in conjunction with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic view of a patient with a counterpulsation systeminstalled including a superficially implanted pump to pump blood to andfrom a shoulder artery.

FIG. 2A is a schematic view of an alternative embodiment including twoconduits coupled to the superficially implanted pump to pump blood totwo different shoulder arteries.

FIG. 2B is a schematic view of another alternative superficiallyimplanted counterpulsation system installed into a patient.

FIG. 2C is a schematic view of another alternative system installed intoa patient.

FIG. 2D is another alternative embodiment of a system installed into thegroin area of a patient.

FIG. 3 is a schematic view of a system similar to that shown in FIG. 1and including a schematic view of a control system and drive system forthe pump.

FIG. 4 is a schematic view of another counterpulsation system installedin a patient.

FIG. 5 is an enlarged view of the pump shown in FIG. 4, and fragmentedto show certain internal details.

FIG. 6 is a cross sectional view of one form of counterpulsation pumpusable in the present invention.

FIG. 7 is a cross sectional view of another alternative embodiment of acounterpulsation pump usable in the present invention.

FIG. 8 is a schematic view illustrating another alternativecounterpulsation system installed in a patient.

FIG. 9 is a cross sectional view of a pump usable in the presentinvention and illustrated in cross section to show an internal bladderin an expanded state.

FIG. 10 is a cross sectional view similar to FIG. 9, but illustratingthe expandable bladder in a compressed state.

FIG. 11 illustrates another alternative system including both acounterpulsation system and a steady or continuous flow pump systeminstalled in a patient.

DETAILED DESCRIPTION OF THE ILLUSTRATIVE EMBODIMENTS

In each of the systems described below, blood is removed from thepatient's arterial blood system during systole and pumped back into theblood system during diastole. In the various figures, like referencenumerals refer to like structure, while like reference numerals withprime marks (') refer to corresponding elements that have been modifiedin manners that will be apparent or described.

FIG. 1 illustrates a patient 10 having a heart 12, shown in longitudinalcross section, coupled with a supplemental assist device or system 14.System 14 comprises a pulsatile pump device 16 which may be implanted ina small pocket made subcutaneously over the patient's chest, such as inthe subclavicular region as shown in the drawing. This is a similarimplantation procedure to conventional pacemakers. Pump 16 is coupledwith a control. Power supply 18 may be an implanted power supply or apower supply partially or wholly external to the patient. Oneparticularly desirable power system comprises a transcutaneous powersupply using a power coil which is periodically charged from outside thebody to continuously operate pump 16. This system is discussed furtherbelow. Pump 16 is coupled with a catheter or conduit 24 which isconnected for fluid communication with a superficial artery 26 in theshoulder region.

As further illustrated in FIG. 1, power supply 18 most preferablycomprises a first coil or power supply portion and a driver unit.Preferably, the driver unit is a fluid driven unit such as a hydraulicunit 19 which has a compliance chamber (not shown) for storing hydraulicfluid. Hydraulic unit 19 is implanted within the body of patient 10,such as in the lower abdominal region, and a second coil or power supplyportion 21 positioned outside the patient's body. Second coil 21 may bein the form of a pack carried on a belt 23 worn by patient 10. Secondcoil 21 includes a first alignment element 25 and a second alignmentelement 27 is carried by an adhesive pad 29 affixed to the skin ofpatient 10. As further shown in FIG. 1, a conduit 31 is connectedbetween driver unit 19 and pump 16 for supplying pressurized air orliquid, such as helium or saline solution, to operate pump 16 asdescribed further below. In various figures below, the power supply andother control components may be deleted solely for clarity.

FIG. 2A illustrates a system similar to that shown in FIG. 1, butillustrating the pump 16 as being external to the patient and connectedvia two conduits 18, 20 simultaneously to two different superficialarteries 26, 28. A movable member 22, such as diaphragm or bladder isshown in pump 16 and moves back and forth to suction blood into the pump16 and expel blood from the pump via both conduits 18, 20.Alternatively, check valves 29 a, 29 b may be used to cause blood to besuctioned into pump 16 via one of conduits 18, 20 and expelled from pump16 via the other of conduits 18, 20.

FIG. 2B illustrates a system similar to FIG. 2A but illustrating analternative connection of blood flow conduits 24, 25 between twodifferent arteries 26, 30 and the pump 16.

FIG. 2C illustrates another alternative similar to FIGS. 2A and 2B, butillustrating another alternative connection between the pump 16 and theaorta 40 via a conduit 41.

FIG. 2D illustrates another possible configuration in which the pump 16is implanted in the pelvic or groin region by performing a less invasiveprocedure which is much less traumatic for the patient thanintrathoracic or intraabdominal procedures. In this embodiment, anartery 42 in the groin region is coupled to at least one conduit 43which is coupled to the pulsatile pump 16. Possible arteries utilized inthis region of the body are the distal aorta, iliac, external iliac,internal iliac or femoral arteries. The pump 16 can be implanted in asuperficial, subcutaneous pelvic area of the body, or in aretroperitoneal location or other pelvic area location.

FIG. 3 illustrates a system similar to those described above, butfurther illustrating a schematic control system 44 including acontroller, power supply and driver. The driver may, for example, be apneumatic or hydraulic device which delivers fluid such as pressurizedair or liquid into and out of the pump 16 via conduit 46 to thereby movean element, such as a diaphragm, bladder, pouch or sack 22 back andforth in controlled or coordinated relation to the patient's heartbeatgenerally as described above in conventional counterpulsationtechniques, and using similar control techniques to ensure proper rhythmand timing during systole and diastole.

FIG. 4 illustrates an alternative system in which the pump 16′ is againexternal to the patient and is connected to a suitable controller/driveunit 52 for pneumatically or hydraulically moving an internal element22′, such as a diaphragm, bladder, pouch, etc., back and forth andthereby moving blood into and out of the pump 16′ and into and out of asuperficially located artery 26 via a conduit 24.

FIG. 5 illustrates an enlarged view of the pump 16′ shown in FIG. 4 and,more specifically, showing the bladder 22′ moving back and forth throughthe effects of introduced and exhausted gas or liquid from a fluidsupply. Saline or other flushing liquid may be introduced throughanother conduit 56 for allowing cleaning operations to take placepreventing or alleviating blood clots.

FIGS. 6 and 7 illustrate two additional alternative pumps 60, 62 withFIG. 6 illustrating another fluid operated bladder 64 which, in thefully activated position shown in phantom lines, either completely or atleast substantially fills the entire void within the pump 60 to preventthe possibility of stagnated blood and resulting blood clots. FIG. 7illustrates the use of an electromagnetic drive which moves the bladder66 via magnets 68 being attracted to and repelled from anelectromagnetic device.

FIG. 8 illustrates another externally positioned counterpulsation pump70 connected to two different superficial arteries 72, 74 forsimultaneously suctioning and expelling blood out of and into arteries26, 28 via conduits 76, 78.

FIGS. 9 and 10 illustrate another embodiment of a counterpulsation pump80 using a bladder, pouch or sack 82 which is operated by theintroduction of pressurized fluid, such as gas or liquid and exhaustionthereof to move bladder 82 back and forth and thereby draw blood intoand discharge blood from an internal space 84 within the pump 80. Asecondary flexible bladder 86 is connected as shown and may becompressed via the introduction of a pressurized fluid as shown in FIG.10 to completely expel blood from the internal space 84. This inhibitsthe formation of blood clots, for example, when the user needs to turnthe pump off for any reason. It may also be desirable to have theposition shown in FIG. 10 as the normal off position of the system as afail safe measure should the patient be disconnected from the powersupply of the unit.

It may also be useful to counterpulse in the presence of a heart assistpump 100, particularly if the pump 100 is not pulsatile (steady flow).Such as a system is shown in FIG. 11. Coronary perfusion occurs indiastole and by timing counterpulsation pump 16, the flow produced by aconstant flow pump 100 can be directed to one or more arteries. Thus, itmay be possible to replace a large bulky left ventricular pump with asmaller steady flow pump 100 and a counterpulsation device 16. Asfurther shown in FIG. 11, pump 100 may be a steady flow pump whichextracts blood from the left side of the heart 12 through a conduit 102and expels the blood through a conduit 104 into a superficial artery 26.Pump 100 may be operated by the same control 18 as pump 16, or by anyother suitable separate control, and may be a hydraulic, pneumatic orelectric pump. The heart assist pump 100 may be comprised of any desiredinternal, external or combined internal/external pump system suited tothe particular patient.

While the present invention has been illustrated by the description ofthe various embodiments thereof, and while the embodiments have beendescribed in considerable detail, it is not intended to restrict or inany way limit the scope of the appended claims to such detail.Additional advantages and modifications will readily appear to thoseskilled in the art. The invention in its broader aspects is thereforenot limited to the specific details, representative apparatus andmethods and illustrative examples shown and described. Accordingly,departures may be made from such details without departing from thescope or spirit of Applicant's general inventive concept.

1. A counterpulsation method of assisting the heart of a patient using apump assist system, the method comprising: coupling a first conduit tothe arterial system of the patient without entering the chest cavity orabdominal cavity of the patient, connecting a pulsatile pump to thefirst conduit, implanting the pump in the patient without entering thechest cavity or abdominal cavity of the patient, connecting a powersupply to the pump, coordinating the operation of the pulsatile pump tosuction blood from the arterial system through the first conduit whilethe heart is in systole and expel the blood into the first conduit andthe arterial system while the heart is in diastole.
 2. The method ofclaim 1, wherein coupling the conduit further comprises coupling to anartery in at least one of the neck, shoulder or upper chest region ofthe patient.
 3. The method of claim 1, wherein coupling the conduitfurther comprises coupling to an artery in the retroperitoneal region ofthe patient.
 4. The method of claim 1, further comprising implanting thepump in a superficial, subcutaneous area of the patient.
 5. The methodof claim 1, further comprising implanting the pump in the pelvic regionof the patient.
 6. A counterpulsation method of assisting the heart of apatient using a pump assist system, the method comprising: coupling afirst conduit to the arterial system of the patient without entering thechest cavity or abdominal cavity of the patient, coupling a secondconduit to the arterial system of the patient without entering the chestcavity or abdominal cavity of the patient, connecting a pump between thefirst and second conduits, implanting the pump in the patient withoutentering the chest cavity or abdominal cavity of the patient, connectinga power supply to the pump, coordinating the operation of the pump tosuction blood from the arterial system through the first conduit whilethe heart is in systole and expel the blood into the arterial systemwhile the heart is in diastole.
 7. The method of claim 6, wherein thecoupling steps further comprise coupling the first and second conduitsto different arteries.
 8. The method of claim 6, wherein the couplingsteps further comprise coupling to arteries in the retroperitonealregion of the patient.
 9. The method of claim 6, further comprisingimplanting the pump in a superficial, subcutaneous area of the patient.10. The method of claim 6, further comprising implanting the pump in thepelvic region of the patient.
 11. A counterpulsation method of assistingthe heart of a patient using a pump assist system, the methodcomprising: coupling a first conduit to the arterial system of thepatient, connecting a pulsatile pump to the first conduit, implantingthe pump in the patient without entering the chest cavity or abdominalcavity of the patient, connecting a power supply to the pump,coordinating the operation of the pulsatile pump to suction blood fromthe arterial system through the first conduit while the heart is insystole and expel the blood into the first conduit and the arterialsystem while the heart is in diastole.
 12. The method of claim 11,further comprising implanting the pump in a superficial, subcutaneousarea of the patient.
 13. A counterpulsation method of assisting theheart of a patient using a pump assist system, the method comprising:coupling a first conduit to the arterial system of the patient withoutentering the chest cavity or abdominal cavity of the patient, connectinga pulsatile pump to the first conduit, connecting a power supply to thepump, coordinating the operation of the pulsatile pump to suction bloodfrom the arterial system through the first conduit while the heart is insystole and expel the blood into the first conduit and the arterialsystem while the heart is in diastole.
 14. The method of claim 13,further comprising: positioning the pump outside of the patient's bodyduring operation of the pump.
 15. The method of claim 13, furthercomprising: coupling a second conduit between the pump and the arterialsystem without entering the chest cavity or abdominal cavity of thepatient.
 16. The method of claim 15, wherein the coupling steps furthercomprise coupling to different arteries.
 17. A pulsatilecounterpulsation pump for use in assisting the heart of a patient, thepump comprising: a pump housing having a chamber and an inlet and anoutlet in fluid communication with said chamber, a movable membermounted in said housing and operable to suction blood into said inlet ina first stroke and expel blood from said outlet in a second stroke, andmeans for evacuating said chamber of at least substantially all blood atthe end of the second stroke.